Globally, malaria in pregnancy leads to severe complications such as abortion, stillbirth, premature delivery, low birth weight, and fetal underdevelopment. This study examined the prevalence and risk factors of malaria among pregnant women attending antenatal care in Osun State, Nigeria. Between July and December 2020, 555 pregnant women from ten primary health centres in Osogbo, Ejigbo and Ilobu Local Government Areas participated in the study. Employing pre-tested questionnaires, qualitative data on the demographic and risk behaviours of participants were obtained. Malaria prevalence, determined by rapid diagnostic tests and blood smear microscopy was 15% caused by Plasmodium falciparum. The highest malaria prevalence was found among women who didn't use insecticides (23.1%), followed by those who did not use insecticide-treated nets (16.5%). The lowest prevalence was among women in their second and third trimesters who had taken Intermittent Preventive Treatment
(IPT) (6.3%). The highest prevalence occurred among women aged 17-24 years (17.4%), while the lowest was among women aged 25-34 years (12.9%). All participants were aware of malaria but their knowledge about transmission (67%), symptoms (64%) and prevention (44%) varied. The study highlights the vulnerability of pregnant women who do not use insecticide-treated nets and emphasizes the need for improved malaria preventive practices. Control efforts should focus on the distribution of insecticide-treated nets, health education during antenatal visits and increased usage of IPT as recommended by the World Health Organization.